Pneumatic hammer



Scpt. l5, 1925.

1,54,128 J. A. c. ROBERTSON NEUMATIG HAMMER Filed April 17. 1924 lPatented Sept. l5, 1925.

UNITED STATES PATENT ersten.

Josera A. c. ROBERTSON', or ronoNfro, onreine.

canapa.

rNnUMarIc Y nannten.`

Appiication medapru 17, 1924. seriaiiwo. 707,239.

To all whom t may concern.'

Be it known that I, Josnrir A. C. Bonner soN, of the city ot Toronto, inthe county of York, Province of Ontario, Canada, a subject of the Kingof Great Britain, have invented certain new and useful Improve- `mentsin Pneumatic Hammers, of which the following is a specification.' y

This invention relates to pneumatic hammers adapted to automaticallyfeed a nail into position under the hammer and to drive it home, and myobject is to provide-aide- Avice of this character whichis of' simplecfFig. 4;;

Fig. 6 a diagrammatic view showing the construction employed to causethe hammer to be reciprocated;

V the plunger tube; and

Fig.. 7 a crosssection of the nail feeding device;

Fig. 8 a Fig. 9 a plan view of Fig. 10 a plan Lview ott horizontalsection ot the same;

the hopper;

the underside of Fig. 11 a plan view of the underside of the base. Y

ln the drawings like numerals of reerence indicate corresponding partsin the diderent figures.

l is a cylinder having exhaust and inlet ports 2 and 3, the lattercommunicates with a valve controlled iiuid supply pipe 4 carried by thecyinder head 5 connected to the cylinder. A handle 6 is also formed onor connected with the head. In the cylinder is slidabiy and rotatablymounted a ham-r mer or piston 7 having a pair of inlet passages 8 and 8and a pair ci" exhaust passages 9 and 9a formed therein. The inletpassage 8 is adapted to lregister with the inlet port 3 to direct the'duid to the top of the cylinder and at thev same time the exhaustpassa-ge 9 is adapted to register with the exhaust port 2 to exhaust theair below l the cylinder and thus cause the piston to `be moveddownwardly in the cylindersee Figs. 1 and 4. `The otherset of passa es8and 9 are adapted to register with t e inlet and outlet. ports and' 2to cause the piston to be moved upwardly 1n the cylinder and there-Vfore the passage 8'* communicates'- with the space below the iston andthe passage 9* communicates wit the space above the piston, vseeFig. 3.

To cause these two sets ovf'passages 8 and 9, 8a and 9,l to alternatelyregister with the inletV and exhaust ports respectively, and thusautomatically causethe piston to be reciprocated, 'the iston at theendof each stroke is partial y rotated' alternatelyy in opposite directionsin the following Inanner. Stationary members 10 and 11 are suit# ablysecured at opposite ends of `the cylinder, the member 1() being locatedat one side of the cylinder and having its lower face` inclined in onedirection. `The member'll is located at the opposite side of the'cylinder and has its upper face inclined in the opposite direction to`the inclined face of the `member 10, These members are tted in recessesformed in the wall of the cylin der and project into the bore thereof.'The piston is provided with inclined shoulders 12 and 13 adaptedtoengage the inclined faces of the members 10 and l1 respectively.yThese shoulders are formed by forming re` cesses 12a and 13 in theperiphery of the piston, the shoulder 12 being inclined in the v. samedirection as the inclined ace of the member 10 and is also of greaterwidth than the latter. With this arrangement as the piston -movesupwardly, with the passages 8 and 9 in register with the ports 3 and 2respectively, see Fig. 3, the shoulder 12 engages the member 10 andrides up the inclined face of the latter which causes the piston` to berotated suiiiciently to cut o the said communications and bring thepassages 8 and 9 into register with the ports 3 and 2 retpectively. Thefluid is then directedlto the space above the piston which forces thelatter downwardly land causes the shoulder 13 to engage the inclinedface of the member 11. This 'shoulder is inclined in the same direction`as the inclined face of the last mentioned member and is of greaterwidth than the latter whereby the piston is partially rotated in theopposite direction to that caused by the engagement of the shoulder 12and the memberlO. The communications between the passages 8 and 9 andthe ports 3 and 2 are thus out off and whichthenailis to be driven.

the passages 8 and 9 are registered with the said ports respectively andthepiston is moved upwardly in the cylinder as here inbefore described.It will readily be seen that with the above construction the pistontuatea nail set4 `orlplunger '14, which isv axially movable v,in a""tube 15,removably carried by the lcylinder 1. 'The tube is slidably mounted onIa-tilbular base 16 Aadapted to rest on ,or against the object, throughy On the base is suitably carried a feed chamber 17 whichcommunicates-with the bore thereof and carries a magazine comprising ahopper 18 and intermediate magazine sections '17* The sections and thehopper have a telescopic connection with one'another and with the feedVchamber so that they may be easily and quickly separated from oneanother or from the `feed chamber.` The 'magazine sections are of curvedtubular shape so that by re- I kmoving one or both of them the hoppermay i be positioned relative to the feed chamber rvsofthat the nails inthe hopper will feed y gravity intothe feed chamber when the device isused in a horizontal aosition. The

' lower end of the hop r is re uced in width so that only one nail at atime can dro into the magazine sections 17'* and the fee chamber 17.

Referring to Figs.- 1, 3 and 5, it will he noted that the plunger 14 isprovided with an integral collar -19 adapted to enga e an annularshoulder 20 formed in the tu e 15 which limits the downward movement ofthe lungerv to prevent it falling through the evice when the latter islifted off the part being nailed. To limit the upward movement` oftheQplunger relative to the tube, the collar 1'9 is adapted to engage abushing 21- carried inthe bottom portion of the cylinderL. The upper endofthe plunger passes through this bushing, which is removable, so thatit may be easily replaced when worn, as it i's important that no fluidleakage should occur at this point. The lower end of the plunger isslidably mounted in the bore ofthe base 16 whereby the plunger, thetube15, and the cylinder 1 maybe moved axially of the base to cause a. nailto be driven home or to permit these parts to be positioned so that anail may be fed into the bore of the base as hereinafter described.

The lower end of the tube 15 is slotted at'22 to provide clearance forthe feed chamber 17 see Fig. 10. To position this slot. relative to thefeed chamber and to limit the upward movement of the tube l5 relative tothe base 16,v a in andl slot connection 23 is provided in t ese parts.To limit the downd ward movement of the ytube 15 relative to the base,the latter is provided with a shoulder 16* adapted to engage the bottomof the said tube.. ,l

Toautomatically feed a nail into the bore of the base 16, when theplunger 14'is raised, I provide a pair of feeders 24 formed of diskshaving eripheral teeth cut therein (see Figs. 7 and) 8) and adapted tobe actuated as follows. The feeders operate through slots formed in thechamber 17 and are secured, with their teeth in vertical alinement, toopposite ends of a tube 25 journalled on an actuating rod 26 which is'ournalled in a pair of brackets 27 secure to the feed chamber 17. Adisk 28 secured to the actuating rod has a. dog 29 pivotally connectedthereto which is adapted to ick a ratchet wheel 30 secured to one of t efeeders 24. The actuating rod has a laterally extending arm 26a formedon or secured thereto, whichr arm is normally held, by means of a spring31, in engagement with the outer surface of the tube 15 as indicated infull lines in Fig. 8. The lower end of `this tube is provided with a cam32 adapted toy engage the arm E 26, when the handle 6 and thus the tube15 is raised, to swing it 'sufficiently to cause the ratchet wheel andthus the Jfeeders to be rotated one tooth forward. This movement causesa. nailfwhich has been fed by gravity from the ho per 18 into the feedchamber 17, to be forced aterally, by the alined teeth a of the feeders,see Fig. 8, through the feed chamber 17 and into the bore of the .base16 where it drops by gravity. This same movement causes the teeth b of.the feeders to engage and single out the first nail from the column ofnails lying in the chamber' 17 and move it forward so that on the nextpartial rotation of the feeders it will be fed forward into the bore ofthe base 16.

,To prevent lateral movement ofthe lower ends of the nails in thechambers, and to prevent the nails striking 4the base and bouncing backinto the chamber' I provide the lower end of the hopper, the chambers 17and 17 and the communication between the chamber 1.7 and the base 16with a channel 33 (see Figs. 1 and 7) of greater width than theremainder of these parts and adapted to receive the heads of the nails.As the nail is forced forward by the feeders 24 it ydrops into thetubular base 16 as hereinbefore described, but as the lower end of thecommunication between the bore of the latter and the chamber 17 is ofless width than the width of the channel, the head of the nan preventslateral movement of the nail with# in the bore of the base.

The nail is positioned in axial alinement` with the plunger 14 by meansof its head engaging the bore of the base 16 and its point enaging acentering groove 34 formed in each of a pair of fingers 35. Thesefingers are pivotally mounted on lugs formed on the lower end of thebase 16 and have their lower ends projecting through a slot formed inthe lower end of the base (see Fig. l1).

l Springs 36 of any suitable shape are ada ted to engage the base andthe upper ends o the fingers to normally hold the lower ends of thelatter in contact with one another and thus centrally position thegrooves 34. When the nail receives its first blow, the

springs permit the fingers to Slightly separate to permit the passageofthe stem of the nail between them. s

To swing the lower ends' of the fingers 35 clear of the head of thenail, the lower end same size as the head of the nail to obtain of thetube 15 is provided with oppositely directed extensions having inclinedfaces 36 formed therein adapted to engage the upper ends of the fingersand squeeze them towards one another (see Fig.

To permit the use of various lengths of spikes or nails having the samesized heads,

the hopper is provided with a plurality ofsets of grooves 37 and 37.Each set of these grooves is adapted to receive and position a falsebottom (not shown) for the hopper so that lthe heads of the nails willbe positioned for 'entry into the channel 33.

As hereinbefore mentioned, the tube is removably carried by the cylinder1, a set screw 38 being provided to hold these parts together, thepurpose of this arrangement is to enable the same cylinder and hammer tobe used with various sized plungers and bases 16 which have to besubstantially'the the best results.

Assuming nails have been placed in the v hopper and the lower end of thebase 16 set against the board to be nailed, the mode of operation is asfollows. The handle is raised te the position shown in lig. 1. whichcauses the actuating rod 26 to be functioned by the cam 32 to move thefeeders to single out the forward nail in the feed chamber and positionit so that when the actuating rod -is again actuated by the cam 32 the.

nail will be forced into the bore of the base 16 and a second nail willbe singled out and positioned for feeding when the handle 6 is againraised to its upper position. This does not occur until the first nailis driven home. and it' will be understood that only the first nailrequires two movements of the rod 26 to position it for engagement withthe plunger 14. The handle 6 is then lowered until the plunger engagesthe head of the neil. the cylinder 1 being supported by the After eachblow of the hammer is imparted tothe nail, the

plunger rests 'on the head-thereof and the tube 15 is slid farther downon the base 16. This tube is yassisted in its downward move-yk inent bymeans ofthe fluid pressure on the bottom of the cylinder when the hammeris being returnedto the top ofthe cylinder. When the lowerend of thetube gets near the shoulder 16, the fingers 35 are engaged by the.inclined faces 36 and squeezed together to permit -thevhead of thenaillto pass lbetween them. When the nail is driven home, the Huid valveis manually closed.

and the handle 6 raised to its upper position, which causes the cam 32to actuate the rod. 26 to cause a partial rotation of the feeders 24 tofeed the second nail into the bore of the base 16 andk at the same `timeto singleout the third nail and position'it for feeding.

' When the device'is used for drivin large nails or spikes, a foot rest39, suitab y carriedl on 'the lower end of the tube 15, enables theoperator to hold the ,device to its uio work. The foot rest is adaptedto bethrownf.

back out of they way or removed `when not required. It will beunderstood that, while i i the terms nail and nail-set have 4been usedthroughout the specification, thedevieemay tok whichV it is suited.

1. In a device of the class describedthe be used for rivetingor anyother purposel combination of a base havinga passage-- therein; a fluidpressure means including s. cylinder slidably mounted on the base; ahammer adaptedI to drive a nail; means for feeding one nail at a timeinto the base passage; a pair of fingers pivoted at the lower -end ofthe base and normally -adapted to contact with one another to center theint of the'nail; and means carried on the `ower end of the cylinder toopen the said fingers to permit the passage of the nail headtherebetween.

2. In a device of the class described the combination of a base having a.passage therein; fluid pressure .means including a cylinder slidab ymounted on the base; a hammer adapted to drive a nail; means for feedingone nail at a time into the base passage; a pair of fingers pivoted onthe lower t e base and provided with a centerend of ing groove adaptedto receive the point of a 130 nail, the base being provided with aslot'to receive the said ngers; springs adapted to normally hold thefingers in contact with one another to centerthe point of the nail;

and means carried on the lower end of the' cylinder to open the saidfingers to permit the passage of the nail headtherebetween. 3. In adevice of the lclassdescribed the combination of a base having 'apassage therein; fluid pressuremeans including :a cylinder slidablymounted on the base; a hammer adapted to drive a 'nail;-'means forfeeding one nail at a timeinto the base passage; apair of fingerspivoted intermediate their ends adjacent the lower end of the base andprovided with centering grooves adapted to receive the point. of a nail,the

vbase being provided 'with 2a slotto receive `the said fingers; springsadapted to engage the upper ends of the v.fingerstofnormally holdthelowerends thereof `contact with one another to 'center the said nailpoint; andmeans carried on thelower end ofthe cylinder for engaging'.the upper ends of the said fingers to spread apart the lower-endsthereof to permit the head ofthe nail to pass through the 'end ofl thebase passage.

4. In a device of the class deseribedthe combination of a base lhaving a*passage therethrough; a chamber carried by theV base communicating withthe 7passage thereof; fluid'pr'essure means adapted to drivelanailincluding' a cylinder slidable on the said base; means vfor feedingone'nailat a time from the chamber into the base passage; ratchet meansfor operatin'gthe said feeding means; an actuating rod foroperating `thesaid ratchet means.;'and a cam `carried by 4the saidy Cylinderandadapted to engage the actuating rodto operate'the feeding means; whenthe cylinder is raised to positionthe fluid pressuremeansfor engagementwith-Ia., fresh nail.

v5.; In a device of the class described the combination of a base havinga. passage therethrough; ya chamber carried by the base communicating-with the "passage thereof; fluid pressure means adapted "to drive anail including acylinder; a ytube detachably connected withthe cylinderand slidably mounted on the base, the tube having a slot adapted toprovide clearance A-f-or the chamber and provided with a cam; a pair `ofrotatable feeders adapted to engage a :nia-il. in the chamber; a ratchetyvvheelsecured to one of the feeders; `a dog adapted to pick the ratchetwheel ;-and\an-actuating rod adapted to operate the dog andnormallyfheldin engagement with the outer surface `of the tube andadapted to beengaged `-byfthe'said ca m to cause the nail` to be forced fromthechamber 4into the basepassage. i

6. In a device ofthe 'class described the combination `of a tubularbase; la chamber carriedv by the baseand communicating with yable by thesaid cam.

the vbore thereof; fluid pressure means adapted to drive a nail includina cylinder; an axially` alined tube detachab y connected therewith andslidably mounted on the tubularbase, the tube having a slot adapted toprovide 'clearance for tlie chamber, a pin and slot connection betweenthe 'tube and the base for positioning the slot relative to the chamberand for limiting the upward movement-of the tube relative to the base;and means for feeding one nail at a time from the chamber into theboreof .the base.

7.111 a device of the class described the combination of a tubular base;a chamber carried by the base and communicating with the bore thereof;fluid pressure means adapted todrive a nail includ-ing a cylinder; anaxially alined tube detachably connected base for positioning the slotrelative to the ychamber and for limiting the upward movement of thetube relative to the base; means vfor feeding one nail at a timefrom thechamber into the bore of the base; and means for automatically actuatingthe feeding means, when the fluid pressure means is raised to positionit for engagement with a vfresh nail. 4 8. In; a device of the class'described the combination of a tubular base; a chamber carried by thesaid base and communicating with the bore thereof; fluid pressure meansadapted to drive ya nail including acylinder having an axially alinedtube detachably connected therewith, the tube being slidably mounted onthe tubular base and being slottedto provide clearance for the chamber;and a pin and slot connection between the tube and the base forpositioning the slot relative to the chamber and for limiting the upwardmovement of the tube relative to the base.

9. In a device of the class described the combination of a tubular base;a chamber carried by the said base and communicating with the borethereof; fluid pressure means ada ted to drive a nail including acylinder having an axially alined tube detachably connected therewith,the tube being slidably mounted on the tubular base and being vslottedto provide clearance for the chamvfrom the chamber into the base bore;and

means for actuating the feeding means oper- 10. In a device of the classdescribed the combination of a tubular base; a chamber carried by thesaid base and communicating the tube having a slot adapted to with thebore thereof, fluid ressure means adapted to drive a nail inclu ing acylinder having an axially alined vtube detachably connected therewith,the tube being slidably mounted on the tubular base and being slotted toprovide clearance for thechamber I and provided with a cam at its lowerend; a

pin and slot connection between the tube and the base for positioningthe slot relative to the chamber and for limiting the upward movement ofthe tube relative to the base; means for feeding one nail at a time fromthe chamber into the base bore; means for actuating the feeding meansoperable by the said cam; fingers adapted to engage the point of a nailto center it in the bore of the base; and means carried by the lower endof the tube for spreading the fingers apart to permit the passage of thenail head between t em.

11. The combination of a base having a passage therethrough; a tubeslidably mounted on the. base; a nail set slidably mounted in the saidpassage; movable fingers carried on the base and adapted to center thepoint of a nail lying in the base passage; and releasing means carriedon the tube for spreading the fingers apart, the tube being adapted tofollow the driven movement o the nail set whereby the releasing meanswill actuate the fingers to provide clearance for the nail head. Y

12. The combination of a base havin a passage therethrough; a tubeslidaly mounted on the base; a nail set slidably mounted in the saidpassage; fingers pivoted intermediate their ends on the base and havingtheir lower ends adapted to contact with one another to centrally locatethe point of a nail; and releasing means carried on the tube adapted toengage the upper ends of the said ngers to spread their lower endsapart, the tube being adapted to follow the driven movement of the nailset whereby the re-` leasing means will actuate the fingers to provideclearance for the nail head.

' 13. In a device of the class described the combination of a base;lafeed chamberi connected therewith; a magazine comprising detachablyconnected curved tubular sec# tions;` and a hopper adapted to bedetachably connected with the cuter end of any one of the sections toenable the device to be used at various angles to its work. t Si ed atToronto, Canada, this 29th day of arch, 1924.

JOSEPH A. C. ROBERTSON.

